lipid-a and Arthritis--Juvenile

Topics: Animals; Antibodies; Antigens, Bacterial; Arthritis, Juvenile; Lectins; Lipid A; Lipopolysaccharides; Mice; O Antigens; Synovial Fluid; Yersinia enterocolitica

To find an optimal method to study antibodies reactive with monophosphoryl lipid A characteristic of oligoarticular arthritis in children.. ELISA using 3 different methods of immobilization were compared, in (1) HCO3 buffer, pH 9.6; (2) HCl, pH 2.0; and (3) methanol. Competitive inhibition studies were carried out to quantitate relative avidity of cross reactions with suspected autoantigens.. Sera from healthy children reacted significantly more strongly with monophosphoryl lipid A after immobilization in acid or in methanol than in a basic buffer. Sera from children with oligoarticular arthritis reacted more strongly than normal sera with the basic buffer method and even more strongly with the methanol method, but were not distinguishable from normal sera with the acid method. Results with individual oligoarticular sera correlated from method to method, but results with normal sera did not. Collagen types I and II, cardiolipin, and denatured DNA can block the anti-monophosphoryl lipid A reactivity to varying degrees on plates prepared with basic buffer, but only collagen type I and DNA block reactivity on plates prepared with methanol.. The epitope on monophosphoryl lipid A recognized by oligoarticular sera is differentially affected by the method of immobilization. The crossreactivity of the anti-monophosphoryl lipid A antibody in this disease is confirmed.

Topics: Antibodies; Arthritis, Juvenile; Buffers; Cations, Divalent; Child; Child, Preschool; Cross Reactions; Enzyme-Linked Immunosorbent Assay; Humans; Infant; Lipid A; Osmolar Concentration

To determine if the germ line gene VH4-34 (VH4.21) encodes the antimonophosphoryl lipid A (MPL) polyspecific antibodies found in oligoarticular arthritis of childhood.. Sera from a range of rheumatic diseases of childhood were assayed for VH4-34 derived antibodies by ELISA using the antiidiotype monoclonal antibody 9G4. Results were compared to assays for anti-MPL antibodies, C4d, and Bb, and for HLA type, joint count, and sedimentation rate.. VH4-34 derived antibodies were elevated in all diseases studied except rheumatoid factor positive polyarticular disease. In oligoarticular arthritis, VH4-34 gene expression correlated with C4d concentration, and VH4-34 encoded globulins were more concentrated in synovial fluid than in blood. No association was found with HLA type. An association between VH4-34 expression and IgG anti-MPL was found in sera from patients from Cincinnati but not from Stanford. No other evidence supported a direct association between VH4-34 derived and anti-MPL antibodies in these children.. The expression of VH4-34 is increased in several rheumatic diseases of childhood, but, as in adults, not in rheumatoid arthritis. VH4-34 expression is not associated with HLA type. The polyspecific autoantibody nature of some VH4-34 derived antibodies may explain the wide range of the unusual antibodies found in oligoarticular arthritis.

Topics: Antibodies; Antibodies, Monoclonal; Arthritis, Juvenile; Complement Activation; Complement System Proteins; Gene Expression; HLA Antigens; Humans; Immunoglobulin Heavy Chains; Immunoglobulin Variable Region; Lipid A; Synovial Fluid; Time Factors

This work was started to determine whether the immunoglobulin G (IgG) reactions with monophosphoryl lipid A (MPL) found in children with arthritis were due to contaminants, a specific site on lipid A, or polyspecific binding. Different lots of MPL were examined by electrophoresis and immunoblot. Competitive inhibition of enzyme-linked immunosorbent assays (ELISAs) by analogs of MPL and biologic materials of clinical interest was used to determine the specificity of the binding site and potential cross-reactions. IgG in all patient sera tested reacted with a single band just < 6.5 kDa on immunoblots of all lots of MPL tested. The ELISAs were inhibited best by analogs of lipid A with an exposed diglucosamine core and intact polar domains. The anti-MPL was also inhibited by fetal bovine collagen types I and II and in some instances by cardiolipin, but not by keratan sulfate, proteoglycan, or DnaK heat shock protein. Lot variation was a persistent technical problem, but no protein contaminant could be demonstrated in any lot. The ELISA and immunoblot results confirmed each other. Immunoblots detected a single band of MPL reactive with IgG. This antibody remains of interest because of its disease association and correlations and because it cross-reacts with collagen and cardiolipin.

Topics: Adult; Antibodies; Antibody Specificity; Antigens; Arthritis, Juvenile; Binding Sites; Carbohydrate Sequence; Child; Cross Reactions; Electrophoresis; Humans; Immunoblotting; Immunoglobulin G; Lipid A; Molecular Sequence Data

IgG antibodies to monophosphoryl lipid A (MPL) are more concentrated in synovial fluids than in the blood of children with pauciarticular juvenile arthritis. Correlations between IgG anti-MPL levels and numbers of inflamed joints were highly significant in 2 of 10 patients followed for 8 years and suggestive in 2 patients followed for shorter periods. A fifth patient had a correlation between IgM anti-MPL and joint count.

Topics: Adolescent; Antibodies; Arthritis, Juvenile; Child; Child, Preschool; Enzyme-Linked Immunosorbent Assay; Humans; Lipid A; Synovial Fluid; Time Factors

IgM antibodies to monophosphoryl-lipid A were found to be elevated in sera from children with all forms of juvenile arthritis (JA) and systemic lupus erythematosus. Of more interest, in patients with pauciarticular JA, IgG antibody titers to monophosphoryl-lipid A were found to be correlated with the C3a concentration and the C3d:C3 ratio. Although the full specificity of these antibodies is unknown, they are the first that have been found to be correlated with complement activation products in any form of JA.

Topics: Arthritis, Juvenile; Autoantibodies; Child; Complement Activation; Complement C3; Complement C4; Cystic Fibrosis; Enzyme-Linked Immunosorbent Assay; Humans; Immunoglobulin G; Immunoglobulin M; Lipid A; Lupus Erythematosus, Systemic; Rheumatoid Factor